Switch for heating pads



Dec. 15, 1942. w, BRADFORD 2,305,132

SWITCH FOR HEATING PADS Filed Dec. 26, 1941 INVENTOR Mu//wmofo/m ATTORNEYS Patented Dec. 15, 1942 UNITED STATES PATENT OFFICE SWITCH FOR HEATING PADS William Bradford, Taunton, Mass.

Application December 26, 1941, Serial No. 424,386

4 Claims.

This invention relates to switches intended particularly for electric heating pads.

It has been customary to supply the operating disk of an electric heating pad switch with projections which would indicate by a sense of touch the position of the switch so that the user could tell its setting in the dark. On account of constructional dimculties it has not been possible to make these projections sufiiciently distinct so that the user would rely with condence upon them. It is the object of this invention to improve the distinctiveness of indicating means for switches of this type. It is a further object to combine with a touch indicating mechanism a visual indicator of an improved form. Additional objects will appear from the following description and claims.

The invention will now be described in connection with the accompanying drawing, in which:

Fig. 1 is a top plan view of a switch made in accordance with the invention;

Fig. 2 is a side elevation thereof, partly broken away;

Fig. 3 is a View similar to Fig. 2 but with the parts in a different position; and

Fig. 4 is a plan view of a disk shown in Figs. 2 and 3.

The improved switch is contained within a casing I and as is customary in the art has switch blades suitably arranged to assume an off position and three heating positions, known as low, medium and high. Since the particular form of switch blades form no part of this invention they have not been shown herein. The switch will be operated in the usual manner from an external projecting handle I I, preferably constructed as a pointer. Within the casing, and rotated with the switch blades by the handle I I, is a disk I2 having its surface formed as a crown cam I3. Reciprocable through apertures in the casing are headed plungers I4; normally held with their stems flush with the casing by springs I5, but projectable beyond the casing by contact with the cam I3. The cam and plungers are preferably proportioned so that in the oil position of the switch none of the plungers project, and in the low, medium and high positions one, two, and three plungers respectively project. The spacing of the plungers may be much greater than has been possible hitherto with the type of projections formed integral with the switch operating disk and also the degree of their projection may be much greater. These features make the indication much more obvious to a sense of touch than has been possible with prior devices.

At the same time a simple visual signal is combined with this structure or may be used separately. This comprises a series of openings I@ in the casing under which an arcuate rib I'I on the disk I2 rotates. The surface of the rib adjacent the apertures is coated with a luminous paint and the apertures and rib are so arranged that in the off position the rib is sheltered by the cover and extends under one, two, and three of the holes respectively when the switch is in low, medium, and high heats.

What I claim is:

l. A multi-heat switch including a casing having two series of apertures, plungers within one of said series of apertures, a rotating switchoperating member mounted in the casing, cam means connected with the switch-operating mechanism for projecting the plungers successively beyond the casing, and a self-luminous device connected with the switch-operating mechanism and movable successively beneath the apertures of the second series.

2. A multi-heat switch including a casing having a series of apertures, a rotating switch-operating member mounted in the casing, and a seliluminous device movable successively beneath said apertures and connected to the switch-operating mechanism.

3. A multi-heat switch including a casing, a rotating switch-operating member mounted therein, a crown cam on said member, a plurality of apertures in the casing, a headed plunger in each of the apertures, and a spring associated with each plunger to maintain its head in engagement with the crown cam, said cam being so shaped as to maintain the plungers normally flush with the casing and to project them successively into single, double, or triple formation as the switch-operating member rotates.

4. A multi-heat switch including an apertured casing, a rotating switch-operating member mounted in the casing, plungers movable outwardly through the apertures in the casing, and cam means coupled to the switch-operating member and so shaped as to project the plungers successively in single, double, or triple formation as the switch-operating member rotates.

WILLIAM BRADFORD. 

